Provide column-select mode (as in Acrobat Reader).

Sometimes, in a scanned document, it is convenient to pick a block of text and
move it to a new location.
For example, the reader  has not sensed that the original text actually has an
embedded frame or a column.
The user can visually see that some part of the text actually does not belong to
the main body of the text, but he has to separate it by laborious cut-and-paste
method, line-by-line.
Further, as he picks the text, the remaining text starts wraping around. This
makes further editing difficult.

If block-sel;ection is available, he can cut out the text in one swift
operation, and let the surrounding text wrap without any problem.

This feature is also very useful to select and delete a block of text.